Does adiponectin explain the lower insulin sensitivity and hyperinsulinemia of African-American children?

Adiponectin is an adipocytokine with antidiabetogenic properties. The present study investigated: (i) the effect of race on adiponectin levels and (ii) the relationship of adiponectin levels in children to insulin sensitivity and secretion. Fasting adiponectin levels were determined in 22 healthy prepubertal black compared with 22 white children of similar body composition. We previously reported these black children to have lower insulin sensitivity and higher first-phase insulin secretion than their white peers. Fasting adiponectin levels were lower in black children (9.9 +/- 1.0 microg/mL vs. 15.7 +/- 1.1 microg/mL, p < 0.001). Adiponectin correlated positively with insulin sensitivity (r = 0.29, p = 0.06) and negatively with first-phase insulin levels (r = -0.47, p = 0.001). In a multiple regression analysis, 48% of the variance in first-phase insulin secretion was explained by the independent effects of race (p = 0.017), adiponectin (p = 0.03), and percentage of body fat (p < 0.001). Adiponectin did not contribute significantly to the variance in insulin sensitivity. In summary, black children have approximately 35% lower adiponectin levels than their white peers. Lower adiponectin does not seem to explain the racial differences in insulin sensitivity. The relationship of hyperinsulinemia and hypoadiponectinemia needs to be further explored.